Gas turbine engines include one or more rotor shafts supported by bearings which, in turn, are supported by annular frames. Frames include an annular casing spaced radially outwardly from an annular hub with a plurality of circumferentially spaced apart struts extending therebetween. The struts may be integrally formed with the casing and hub in a common casting, for example, or may be suitably bolted thereto. The bearings are supported by the frame and within the hub.
The struts are hollow so pressurized cooling air may pass through and be routed into the hub. The pressurized air may provide rotor purge for the high pressure and low pressure turbines through holes in the hub. The air also provides cooling for the strut and hub in addition to service lines and tubes contained within the struts which service an aft high pressure rotor bearing. It is important that the pressurized air within the strut and hub not be lost due to leakage. If leakage occurs, the rotor cavity temperatures will be adversely affected.
The pressurized cooling air is supplied to the struts by an air manifold system. The air manifold system typically includes three or four or more manifold assemblies including a bleed air supply pipe or duct for conveying bleed air from the compressor to a manifold which includes supply ducts leading to caps covering radially outer inlets to the hollow frame struts. State of the art manifolds are formed welded tube rigidly mounted to an engine casing. Jumper tubes with piston ring seals (or sealing) have also been used. The rigidly mounted manifolds are heavy, costly, and tend to have high cycle fatigue and fit-up problems. Jumper tubes with piston ring designs tend to have wear durability problems, reduced angular misalignment capability, and increased leakage. Thus, it is desirable to have a manifold and manifold assembly that reduces and/or eliminates these problems.